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Using both magnesium chloride and magnesium sulfate will keep the ionic balance closer to natural seawater, but using only magnesium sulfate likely is acceptable. Using only magnesium chloride probably is good enough. The ratio when using both is 10:1 magnesium chloride to magnesium sulfate.

Using both magnesium chloride and magnesium sulfate will keep the ionic balance closer to natural seawater, but using only magnesium sulfate likely is acceptable. Using only magnesium chloride probably is good enough. The ratio when using both is 10:1 magnesium chloride to magnesium sulfate.

I read somewhere that you don't want to use just magnesium chloride if you're already using calcium chloride.

Could I use just magnesium chloride instead of magnesium sulfate if I'm using calcium chloride since the suggested ratio is 10:1?

That formula would be used only for maintaining the magnesium level. For raising it, calcium chloride alone should be okay.

Thanks for the link, in your last sentence did you mean to say magnesium chloride rather than calcium chloride?

I don't have any espom salts. I will probably purchase some dr foster magnesium chloride for the short term to raise it, then later get dr foster magnesium sulfate to form a ratio for maintaining the magnesium in my maintenance schedule.

Is Arm and Hammer baking soda cheaper than a $10 3.5LB bottle of calcium bicarbonate from Dr fosters?

That's correct when dosing for magnesium consumption. When raising the magnesium level due to an issue with the salt product, there's no corresponding ionic shift from the two-part, so using the 10:1 ratio is correct, well, assuming the salt product has a reasonable chloride to sulfate ratio.